gzip: stdin: decompression OK, trailing garbage ignored
I did get this error un-tarring the package. That's a delayed error from an earlier file in the package with "trailing garbage" (whatever that is). In my case, at least, the module still compiled and installed successfully.

It doesn't inspire great confidence in the vendor's package, I know. But it seems to work.

For what it's worth, the hardware support pages indicate that the problem with the ethernet port has been resolved with UNR 9.10 (Karmic). I haven't tried it myself, yet.

I should probably have added that if you compile the driver, you'll have to re-compile with each kernel upgrade.